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M31, The Andromeda Galaxy

M31, The Andromeda Galaxy, is a gigantic collection of more than 1 trillion stars that is located about 2.5 million light years away in the Constellation of Andromeda.

The Andromeda Galaxy is one of the farthest objects that can be seen with the unaided eye, appearing as a faint smudge of light when viewed under dark skies far from the light pollution of civilization. As we look at M31 we are really seeing the way it looked 2.5 million years ago because that is how long it took the light to reach us.

Exposure Data
  • Lens: Canon 300mm f/2.8 L USM IS telephoto lens
  • F/stop: f/2.8
  • Exposure: Composite of 57 frames, each 2 minutes long for a total of 114 minutes exposure
  • Mount: Polar-aligned tracking equatorial mount, auto-guided
  • Camera: Canon EOS 20Da DSLR
  • Mode: Raw
  • ISO: 1600
  • White Balance: Daylight
  • In-Camera Noise Reduction: Off
  • Filter: IDAS LPS
  • Temp: 52F
  • Time: 9:22 p.m. EDT
  • Date: September 27, 2005
  • Location: Scott's Pitt, NJ
  • Calibration: Darks: 16 x 2 min dark frames averaged together as a master dark. Auto-dark calibrated each light frame in Images Plus v2.75beta. No Flats, no bias.
  • Processing: Automatic Image Set Processing in Images Plus v2.75 where all light CR2 raw files were converted to 16-bit linear TIFF files with No White Balance, Color Filter Array as the white balance type, then calibrated with the master dark. The light frames were then Bayer interpolated to convert them to color images. The light frames were then registered and aligned in Images Plus. The light frames were then composited together and "stacked" in Images Plus using min-max excluded as the method. Digital Development was then applied to this 16-bit linear master light file. The image was corrected for vignetting with GradientXTerminator. Color balance was then adjusted with levels and curves modifications. Color saturation was increased. A high-pass filtered copy of the background layer was blended via lighten mode in Photoshop CS2. Noise Ninja was used to reduce noise in the image.

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